Hey,

I have a PC. When I play some games, it eventually shuts down for no apparent reason. It doesn't reboot, it just powers off completely. Actually, the last time was different: I could hear the HDD being active, and at least one or two cooling fans, I think the CPU and case fan, were still running. I didn't get any signal to the monitor, though, and could do nothing but force the computer off by holding down the power button for a few seconds.

This hasn't occurred in all games. I've been playing Playerunknown's Battlegrounds and Battlefield 1 without the issue. Warhammer End Times: Vermintide eventually leads to a shutdown every time, however, and that latest crash was in Counter-Strike Global Offensive. Before that, I had clocked nearly a thousand hours in CSGO without my system ever crashing.

I just ran Aida64's stress test overnight for over six hours. My CPU and GPU got pretty hot, nothing too crazy but high figures as you'd expect from such a test, but there was no crash.

I have the latest drivers and all that jazz. i5-6600K, AMD RX480, Windows 10. If anything, I'm thinking it could be the PSU, but then why did it handle the stress test just fine?

Wow. I'm no computer doc, but I just had to replace my laptop's HD (losing years worth of projects, nice), but I can imagine there's quite a few things that can be wrong with it:

-- HDD physical issues (what I had, heh)
Article on checking HDD integrity: https://www.maketecheasier.com/check-hard-disk-health-windows/
-- power supply (that's what I first thought of when you described the issue)
Article about testing power: https://www.lifewire.com/how-to-test-the-power-supply-in-computer-2626129 (sounds like might be better just to bring it to the shop)
-- something with the motherboard?

Ah, yes, PSU = Power Supply Unit. What I'd do is I'd probably get it examined by a specialist, because I've no idea what I'm talking about.

Thanks for the ideas, Koobie.

I reverted the monitor's refresh rate to 60 Hz. I had overclocked it to 71 Hz, and while I had no other problems, maybe that was the culprit behind these shutdowns. I've not had another shutdown today, at least, despite playing a bit of Vermintide.

Inspect your motherboard and video card for any capacitors that may be damaged.

https://www.google.com/search?q=motherboard+capacitor+failure+symptoms&oq=motherboard+capacitor+failure+symptoms&gs_l=psy-ab.3..0.10290.12374.0.12477.9.9.0.0.0.0.129.760.0j6.6.0....0...1.1.64.psy-ab..3.6.758.cEF-JxMMv3I